Information with regard to the rate of sand migration in deserts, beaches and the like is of interest to many geologists as well as other persons in the scientific community. Some devices have been developed for trapping and collecting wind driven sand. These devices take a variety of forms and, in general, provide some form of entrance opening or openings through which the sand enters the trap and a collection chamber to which the sand falls by gravity. The sand collected in the collection chamber is removed therefrom for weighing to thereby enable one to determine the amount of sand which has moved through an area during a given period. A number of sand traps were evaluated in Horikawa, K. and Shen, H. W., "Sand Movement by Wind Action", Beach Erosion Board, Office of the Chief of Engineers, Technical Memorandum No. 119, Dept. of the Army, Corps. of Engineers, (U.S.A.), 51 pp. and appendices (1960). A further background reference of interest is Bagnold, R. A., "Physics of Blown Sand and Desert Dunes", Meuthen, London, 265 pp. (1954). Other work in this area, including the design of a sand and soil aggregate catching device, has been done by U.S. Department of Agriculture, Wind Erosion Laboratory, Manhattan, Kansas. A distinction should be made between particles in suspension and sand drift migration by wind action. The latter is generally thought to be comprised of three distinct sub-processes, viz., (i) saltation, (ii) suspension and (iii) surface creep. As defined in the A.G.I. Glossary published by the American Geological Institute, Washington, D.C. (1973), saltation is a mode of sediment transport in which the particles are moved progressively forward in a series of short intermittent leaps, jumps, hops or bounces from a bottom surface. Examples are sand particles which "skip" downwind by impact and rebound along a desert surface, or "bounce" downstream under the influence of eddy currents that are not turbulent enough to retain the particles in suspension and thereby return the particles to the stream bed at some distance downstream. Suspension is defined as a mode of sediment transport in which upward currents in eddies of turbulent flow are capable of supporting the weight of undissolved sediment particles and indefinitely holding and maintaining the particles in the surrounding fluid. Examples are silt in water and dust in air. Surface creep is the slow downwind advance of large sand grains along a surface by impact of smaller grains in saltation.
There are, of course, many examples of devices used in trapping and/or collecting particles in suspension, e.g., dust collectors, and the like. Examples of such devices are disclosed in U.S. Pat. Nos. 1,437,866 (Shurtleff); 2,353,828 (Hyde); 2,962,122 (Linderoth); 3,296,858 (Doury et al); 3,787,123 (Sigrist); 3,914,979 (Shofner).